1. Field of the Invention
This invention relates to an information recording or erasing apparatus.
2. Description of the Prior Art
Recording or erasing apparatuses of the kind using a recording medium such as a magnetic sheet or magnetic tape which permits information writing or recording thereon or erasing of recorded information therefrom are apt to have drawbacks in that information may be recorded by mistake on a wrong track which already has information recorded thereon or existing recorded information may be inadvertently erased. In a conventional known method, such errors have been prevented by providing a cassette with means for inhibiting recording information in or erasing recorded information from the recording medium (such as an erroneous erasing preventing claw). When a cassette having this device set in a record or erase inhibiting mode is loaded on the recording or erasing apparatus, the apparatus is inhibited from recording or erasing. In cases where new information is to be recorded by erasing existing recorded information from the recording medium contained in the cassette which has been set in the write or erase inhibiting mode, the cassette must be somehow modified to bring it back to an original state from the inhibiting mode.
In another known prior art method for preventing the above-stated errors, the cassette containing a recording medium is provided with a counter which is arranged to indicate the amount of the recording medium which has been used such as the length of the tape portion or the number of recording tracks that have been used for recording. In that case, when the apparatus is loaded with the cassette containing a partially recorded recording medium, the cassette is arranged to render the apparatus incapable of recording or erasing within a part of the recording medium indicated by the counter and to allow the apparatus to perform recording only on the remaining portion of the recording medium after the indicated part. With this method applied to a recording or erasing apparatus, if new information is to be recorded by erasing the recorded information existing in the recorded portion of the recording medium, the counter indication on the cassette must be adjusted to a recording track to be used for recording the new information.
All the methods of the prior art described above thus necessitate some additional work on the cassette or the counter in cases where information is to be newly written or recorded on the recording medium. This has degraded the operability of the apparatus. The inconvenience resulting from the degraded operability increases especially in a case where such work is required when the apparatus has already been loaded with the cassette because the cassette must once again be taken out from the body of the apparatus.